package com.discovery.configurer;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;

/**
 * @Author xuebinlu
 * @Date 2018/5/9 9:46
 * @Version 1.0
 * @Description Jackson 配置
 **/
@Configuration
public class JacksonConfig {


    // 通过该方法对mapper对象进行设置，所有序列化的对象都将按改规则进行系列化
    // Include.Include.ALWAYS 默认
    // Include.NON_DEFAULT 属性为默认值不序列化
    // Include.NON_EMPTY 属性为 空（""） 或者为 NULL 都不序列化，则返回的json是没有这个字段的。这样对移动端会更省流量
    // Include.NON_NULL 属性为NULL 不序列化,就是为null的字段不参加序列化
    //objectMapper.setSerializationInclusion(Include.NON_EMPTY);

    @Bean
    @Primary
    @ConditionalOnMissingBean(ObjectMapper.class)
    public ObjectMapper jacksonObjectMapper(Jackson2ObjectMapperBuilder builder)
    {
        ObjectMapper objectMapper = builder.createXmlMapper(false).build();
        objectMapper.setSerializationInclusion(JsonInclude.Include.NON_EMPTY);
        return objectMapper;
    }

     /*  字段保留，将null值转为""
        objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>()
    {
        @Override
        public void serialize(Object o, JsonGenerator jsonGenerator,
            SerializerProvider serializerProvider)
                    throws IOException, JsonProcessingException
        {
            jsonGenerator.writeString("");
        }
    });*/
}
